From the Guidelines
Two-thirds maintenance fluids should be used in hospitalized patients to reduce the risk of hyponatremia and fluid overload, as recommended by recent guidelines and supported by physiological principles 1. The use of 2/3 maintenance fluids is a strategy to balance the need for adequate hydration with the risk of developing complications such as hyponatremia, fluid overload, and hyperchloremic acidosis. Key points to consider when using 2/3 maintenance fluids include:
- Monitoring electrolytes, especially sodium levels, to adjust the fluid prescription based on the patient's clinical status
- Recognizing that hospitalized patients often have increased antidiuretic hormone (ADH) secretion, which reduces free water excretion and makes them susceptible to dilutional hyponatremia if given full maintenance fluids with low sodium content
- Understanding that the standard calculation for maintenance fluids may provide excessive free water, leading to hyponatremia in certain patient populations, such as children and postoperative patients The ESPNIC clinical practice guidelines, published in 2022, provide evidence-based recommendations for intravenous maintenance fluid therapy in acute and critically ill children, highlighting the importance of considering the tonicity, electrolyte content, and volume of fluid administered 1. By using 2/3 maintenance fluids, clinicians can provide adequate hydration while minimizing the risk of complications, ultimately improving patient outcomes in terms of morbidity, mortality, and quality of life.
From the Research
Maintenance Fluids
- The use of 2/3 maintenance fluids is not directly addressed in the provided studies 2, 3, 4, 5, 6.
- However, the studies discuss the importance of fluid management in patients with heart failure and fluid overload 2, 3, 4.
- The "5B" approach is suggested for managing fluid overload in heart failure patients, which includes balance of fluids, blood pressure, biomarkers, bioimpedance vector analysis, and blood volume 3.
- The use of diuretics and ultrafiltration can achieve volume control in patients with heart failure 4.
- The choice of maintenance fluid composition is important, with evidence suggesting that isotonic fluids may be preferred over hypotonic fluids to avoid hyponatremia 5.
- Maintenance fluids can impose a significant fluid, sodium, and chloride burden on critically ill patients, and fluid creep can contribute to this burden 6.
Fluid Management
- Fluid management is crucial in patients with heart failure, and a tailored approach is necessary to manage the underlying pathophysiology 2, 3.
- The effective and safe use of diuretics requires a physiological understanding of their pharmacokinetics and pharmacodynamics, as well as an appreciation of the clinical goals of diuretic therapy 4.
- The use of continuous infusions of loop diuretics, sometimes combined with other diuretics, can be effective in patients with advanced heart failure 4.
- Ultrafiltration by semipermeable membranes can achieve targeted fluid removal in patients who do not respond to diuretic therapy 4.